Mae said, "Bacterial colonies. We've got some contamination of the coli stock. I had to take one tank offline. We're trying to figure out what's wrong."

"Probably phage, don't you think?" Julia said. "Isn't that what it usually is with bacterial stocks-a virus?" She sighed. "Everything about molecular manufacturing is so delicate. Things go wrong so easily, and so often. You have to keep alert for trouble." She glanced at me, and at Mae. "But surely this isn't what you've been looking at all this time ..."

"Actually, it is," I said.

"What? Pictures of mold?"

"Bacteria."

"Yes, bacteria. You've been looking at this the whole time, Mae?"

She shrugged, nodded. "Yes, Julia. It's my job."

"And I don't question your dedication for a moment," Julia said. "But do you mind?" Her hand darted forward and hit the back key in the corner of the keyboard. The previous screen showed more pictures of bacterial growth.

The next screen showed a virus electron micrograph.

And then a table of growth data over the last twelve hours.

Julia continued to hit the back key half a dozen times more, but all she saw were images of bacteria and viruses, graphs, and data tables. She took her hand away from the keyboard. "You seem to be devoting a lot of time to this. Is it really so important?"

"Well, it's a contaminant," Mae said. "If we don't control it, we'll have to shut down the entire system."

"Then by all means keep at it." She turned to me. "Want to have breakfast? I'd imagine you must be starving."

"Sounds great," I said.

"Come with me," Julia said. "We'll make it together."

"Okay," I said. I glanced at Mae. "I'll see you later. Let me know if I can do anything to help."

I left with Julia. We started down the corridor to the residences.

"I don't know why," Julia said, "but that woman bothers me."

"I don't know why either. She's very good. Very thoughtful, very conscientious."

"And very pretty."

"Julia ..."

"Is that why you won't kiss me? Because you're involved with her?"

"Julia, for Christ's sake."

She stared at me, waiting.

"Look," I said. "It's been a rough couple of weeks for everybody. Frankly, you've been difficult to live with."

"I'm sure I have."

"And frankly, I've been pretty angry with you."

"With good reason, I know. I'm sorry for what I put you through." She leaned over, kissed me on the cheek. "But it feels so distant now. I don't like the tension between us. What do you say we kiss and make up?"

"Maybe later," I said. "We have a lot to do now."

She got playful, puckering her lips, kissing air. "Oooh, come on, sweetie, just a little smooch ... come on, it won't kill you ..."

"Later," I said.

She sighed, and gave up. We continued down the corridor in silence for a while. Then she said, in a serious voice, "You're avoiding me, Jack. And I want to know why." I didn't answer her, I just gave a long-suffering sigh and kept walking, acting like what she'd said was beneath response. In fact, I was badly worried.

I couldn't keep refusing to kiss her forever; sooner or later she'd figure out what I knew. Maybe she already had. Because even when Julia was acting girlish, she seemed sharper, more alert than she'd ever been before. I had the feeling she didn't miss anything. And I had the same feeling about Ricky. It was as if they were tuned up, ultra-aware. And I was worried about what I'd seen on Mae's monitor. The black cloud that seemed to come from Julia's mouth. Had it really been there, on the video? Because as far as I knew, swarms killed their prey on contact. They were merciless. Now Julia seemed to be harboring a swarm. How could that be? Did she have some sort of immunity? Or was the swarm tolerating her, not killing her for some reason? And what about Ricky and Vince? Did they have immunity, too?

One thing was clear: Julia and Ricky did not want us to call anybody. They had deliberately isolated us in the desert, knowing that they would have only a few hours until the helicopter arrived. So apparently, that's all the time they needed. To do what? Kill us? Or just infect us? What?

Walking down the corridor next to my wife, I felt as if I was walking with a stranger. With somebody I didn't know anymore. Somebody who was immensely dangerous. I glanced at my watch. The helicopter would be here in less than two hours, now.

Julia smiled. "Got an appointment?"

"No. Just thinking it's time for breakfast."

"Jack," she said. "Why won't you be honest with me?"

"I'm being honest ..."

"No. You were wondering how long until the helicopter comes."

I shrugged.

"Two hours," she said. And she added, "I'll bet you'll be glad to get out of here, won't you?"

"Yes," I said. "But I'm not leaving until everything is done."

"Why? What's left to be done?"

By now we had reached the residential unit. I could smell bacon and eggs cooking. Ricky came around the corner. He smiled heartily when he saw me. "Hey, Jack. How'd you sleep?"

"I slept okay."

"Really? 'Cause you look a little tired."

"I had bad dreams," I said.

"Oh yes? Bad dreams? Bummer."

"It happens sometimes," I said.

We all went into the kitchen. Bobby was making breakfast. "Scrambled eggs with chives and cream cheese," he said cheerfully. "What kind of toast do you guys want?" Julia wanted wheat toast. Ricky wanted English muffin. I said I didn't want anything. I was looking at Ricky, noticing again how strong he appeared. Beneath his T-shirt, the muscles were well defined, cut. He caught me staring at him. "Something wrong?"

"No. Just admiring your butch look." I tried to be light, but the truth was that I felt incredibly uncomfortable in the kitchen with all of them around me. I kept thinking of Charley, and how swiftly they had attacked him. I wasn't hungry; I just wanted to get out of there. But I couldn't see how to do it without arousing suspicion.

Julia went to the refrigerator, opened the door. The champagne was in there. "You guys ready to celebrate now?"

"Sure," Bobby said. "Sounds great, a little mimosa in the morning ..."

"Absolutely not," I said. "Julia, I'm going to insist you take this situation seriously. We're not out of the woods yet. We have to get the Army in here, and we haven't been able to call. It's not time to break out the champagne."

She pouted. "Oh, you're such a spoilsport ..."

"Spoilsport hell. You're being ridiculous."

"Oooh, baby, don't get mad, just kiss me, kiss me." She puckered her lips again, and leaned across the table.

But it seemed like getting angry was the only move I had. "God damn it, Julia," I said, raising my voice, "the only reason we are in this mess is because you didn't take it seriously in the first place. You had a runaway swarm out there in the desert for what-two weeks? And instead of eradicating it, you played with it. You fooled around until it got out of control, and as a result three people are dead. This is not a goddamn celebration, Julia. It's a disaster. And I am not drinking any fucking champagne while I am here and neither is anyone else." I took the bottle to the sink and smashed it. I turned back to her. "Got it?"

Stony-faced, she said, "That was completely unnecessary."

I saw Ricky looking at me thoughtfully. As if he was trying to decide something. Bobby turned his back while he cooked, as if he was embarrassed by a marital spat. Had they gotten to Bobby? I thought I saw a thin black line at his neck, but I couldn't be sure, and I didn't dare stare.

"Unnecessary?" I said, full of outrage. "Those people were my friends. And they were your friends, Ricky. And yours, Bobby. And I don't want to hear this celebration shit anymore!" I turned and stomped out of the room. As I left, Vince was coming in. "Better take it easy, pal," Vince said. "You'll give yourself a stroke."

"Fuck off," I said.

Vince raised his eyebrows. I brushed past him.

"You're not fooling anybody, Jack!" Julia called after me. "I know what you're really up to!"

My stomach flipped. But I kept walking.

"I can see right through you, Jack. I know you're going back to her."

"Damn right!" I said.

Was that what Julia really thought? I didn't believe it for a moment. She was just trying to mislead me, to keep me off guard until ... what? What were they going to do? There were four of them. And only two of us-at least, there were two if they hadn't already gotten to Mae.

Mae wasn't in the biology laboratory. I looked around and saw that a side door was ajar, leading downstairs to the underground level where the fermentation chambers were installed. Up close, they were much larger than I had realized, giant stainless spheres about six feet across. They were surrounded by a maze of pipes and valves and temperature control units. It was warm here, and very noisy.

Mae was standing by the third unit, making notes on a clipboard and shutting a valve. She had a rack of test tubes at her feet. I went down and stood beside her. She looked at me, then shot a glance toward the ceiling, where a security camera was mounted. She walked around to the other side of the tank, and I followed her. Over here, the tank blocked the camera. She said, "They slept with the lights on."

I nodded. I knew what it meant, now.

"They're all infected," she said.

"Yes."

"And it's not killing them."

"Yes," I said, "but I don't understand why."

"It must have evolved," she said, "to tolerate them."

"That fast?"

"Evolution can happen fast," she said. "You know the Ewald studies." I did. Paul Ewald had studied cholera. What he found was that the cholera organism would quickly change to sustain an epidemic. In places where there were no sanitary water supplies but perhaps a ditch running through a village, the cholera was virulent, prostrating the victim and killing him where he fell from massive overwhelming diarrhea. The diarrhea contained millions of cholera organisms; it would run into the water supply and infect others in the village. In this way the cholera reproduced, and the epidemic continued.

But when there was sanitary water supply, the virulent strain could not reproduce. The victim would die where he fell but his diarrhea would not enter the water supply. Others would not be infected, and the epidemic would fade. Under those circumstances, the epidemic evolved to a milder form, enabling the victim to walk around and spread the milder organisms by contact, dirty linens, and so on.

Mae was suggesting that the same thing had happened to the swarms. They had evolved to a milder form, which could be transmitted from one person to another. "It's creepy," I said.

She nodded. "But what can we do about it?"

And then she began to cry silently, tears running down her cheeks. Mae was always so strong. Seeing her upset unnerved me now. She was shaking her head. "Jack, there's nothing we can do. There's four of them. They're stronger than we are. They're going to kill us the way they killed Charley."

She pressed her head against my shoulder. I put my arm around her. But I couldn't comfort her. Because I knew she was right.

There was no way out.

Winston Churchill once said that being shot at focused the mind wonderfully. My mind was going very fast now. I was thinking that I had made a mistake and I had to fix it. Even though it was a typically human mistake.

Considering that we live in an era of evolutionary everything-evolutionary biology, evolutionary medicine, evolutionary ecology, evolutionary psychology, evolutionary economics, evolutionary computing-it was surprising how rarely people thought in evolutionary terms. It was a human blind spot. We looked at the world around us as a snapshot when it was really a movie, constantly changing. Of course we knew it was changing but we behaved as if it wasn't. We denied the reality of change. So change always surprised us. Parents were even surprised by the maturing of their own children. They treated them as younger than they really were. And I had been surprised by the change in the evolution of the swarms. There was no reason why the swarms shouldn't evolve in two directions at the same time. Or three, or four, or ten directions, for that matter. I should have anticipated that. I should have looked for it, expected it. If I had, I might be better prepared to deal with the situation now. But instead I had treated the swarm as one problem-a problem out there, in the desert-and I had ignored other possibilities.

It's called denial, Jack.

I started to wonder what else I was denying now. What else I had failed to see. Where did I go wrong? What was the first clue I had missed? Probably the fact that my initial contact with a swarm had produced an allergic reaction-a reaction that almost killed me. Mae had called it a coliform reaction. Caused by a toxin from the bacteria in the swarm. That toxin was obviously the result of an evolutionary change in the E. coli that made up the swarm. Well, for that matter, the very presence of phage in the tank was an evolutionary change, a viral response to the bacteria that-

"Mae," I said. "Wait a minute."

"What?"

I said, "There might be something we can do to stop them."

She was skeptical; I could see it in her face. But she wiped her eyes and listened.

I said, "The swarm consists of particles and bacteria, is that right?"

"Yes ..."

"The bacteria provide the raw ingredients for the particles to reproduce themselves. Right? Okay. So if the bacteria die, the swarm dies too?"

"Probably." She frowned. "Are you thinking of an antibiotic? Giving everyone an antibiotic? Because you need a lot of antibiotics to clear an E. coli infection, they'd have to take drugs for several days, and I don't-"

"No. I'm not thinking of antibiotics." I tapped the tank in front of me. "I'm thinking of this."

"Phage?"

"Why not?"

"I don't know if it will work," she said. She frowned. "It might. Except ... how're you going to get the phage into them? They won't just drink it down, you know."

"Then we'll fill the atmosphere with it," I said. "They'll breathe it in and they'll never know."

"Uh-huh. How do we fill the atmosphere?"

"Easy. Don't shut down this tank. Feed the bacteria into the system. I want the assembly line to start making virus-a lot of virus. Then we release into the air." Mae sighed. "It won't work, Jack," she said.

"Why not?"

"Because the assembly line won't make a lot of virus."

"Why not?"

"Because of the way the virus reproduces. You know-the virus floats around, attaches to a cell wall, and injects itself into the cell. Then it takes over the cell's own RNA, and converts it to making more viruses. The cell ceases all its normal metabolic functions, and just cranks out viruses. Pretty soon the cell is packed with viruses, and it bursts like a balloon. All the viruses are released, they float to other cells, and the process starts all over."

"Yes ... so?"

"If I introduce phage into the assembly lines, the virus will reproduce rapidly-for a while. But it will rupture a lot of cell membranes, leaving behind all those membranes as a lipid crud. The crud will clog the intermediate filters. After about an hour or two, the assembly lines will start to overheat, the safety systems will kick in, and shut everything down. The whole production line will just stop. No virus."

"Can the safety systems be turned off?"

"Yes. But I don't know how."

"Who does?"

"Only Ricky."

I shook my head. "That won't do us any good. Are you sure you can't figure out-"

"There's a code," she said. "Ricky's the only one who knows it."

"Oh."

"Anyway, Jack, it'd be too dangerous to turn off the safeties. Parts of that system operate at high temperature, and high voltages. And there's a lot of ketones and methane produced in the arms. It's continuously monitored and drawn off to keep the levels below a certain concentration. But if it isn't drawn off, and you start high voltage sparking ..." She paused, shrugged.

"What're you saying? It could explode?"

"No, Jack. I'm saying it will explode. In a matter of minutes after the safeties are shut off. Six, maybe eight minutes at most. And you wouldn't want to be there when that happens. So you can't use the system to produce a lot of virus. Safeties on or safeties off, it just won't work." Silence.

Frustration.

I looked around the room. I looked at the steel tank, curving upward over my head. I looked at the rack of test tubes at Mae's feet. I looked in the corner, where I saw a mop, a bucket, and a one-gallon plastic bottle of water. And I looked at Mae, frightened, still on the verge of tears, but somehow holding it together.

And I had a plan.

"Okay. Do it anyway. Release the virus into the system."

"What's the point of that?"

"Just do it."

"Jack," she said. "Why are we doing this? I'm afraid they know that we know. We can't fool them. They're too clever. If we try to do this, they'll be onto us in a minute."

"Yes," I said. "They probably will."

"And it won't work, anyway. The system won't make viruses. So why, Jack? What good will it do?"

Mae had been a good friend through all this, and now I had a plan and I wasn't going to tell her. I hated to do it this way, but I had to make a distraction for the others. I had to fool them. And she had to help me do it-which meant she had to believe in a different plan. I said, "Mae, we have to distract them, to fool them. I want you to release the virus into the assembly line. Let them focus on that. Let them worry about that. Meanwhile, I'll take some virus up to the maintenance area beneath the roof, and dump it into the sprinkler reservoir."

"And then set the sprinklers off?"

"Yes."

She nodded. "And they'll be soaked in virus. Everybody in this facility. Drenched."

"Right."

She said, "It just might work, Jack."

"I can't think of anything better," I said. "Now open one of those valves, and let's draw off some test tubes of virus. And I want you to put some virus into that gallon jug over there." She hesitated. "The valve is on the other side of the tank. The security camera will see us."

"That's okay," I said. "It can't be helped now. You just have to buy me a little time."

"And how do I do that?"

I told her. She made a face. "You're kidding! They'll never do that!"

"Of course not. I just need a little time."

* * *

We went around the tank. She filled the test tubes. The liquid that came out was a thick brown slop. It smelled fecal. It looked fecal. Mae said to me, "Are you sure about this?"

"Got to do it," I said. "There's no choice."

"You first."

I picked up the test tube, took a breath, and swallowed it whole. It was disgusting. My stomach heaved. I thought I would vomit, but I didn't. I took another breath, swallowed some water from the gallon jug, and looked at Mae.

"Awful, huh?" she said.

"Awful."

She picked up a test tube, held her nose, and swallowed. I waited through her coughing fit. She managed not to vomit. I gave her the gallon jug, she drank, and poured the rest out onto the floor. Then she filled it with brown slop.

The last thing she did was twist the handle of a big flow valve. "There," she said. "It's going into the system now."

"Okay," I said. I took two test tubes and stuck them in my shirt pocket. I took the gallon jug. It said ARROWHEAD PURE WATER on the label. "See you later." And I hurried off. As I went down the hallway, I figured there was one chance in a hundred that I would succeed. Maybe only one chance in a thousand.

But I had a chance.

Later on, I watched the entire scene on the security camera, so I knew what happened to Mae. She walked into the kitchen, carrying her rack of brown test tubes. The others were all there, eating. Julia gave her a frosty look. Vince ignored her. Ricky said, "What've you got there, Mae?"

"Phage," she said.

"What for?"

Now Julia looked over. Mae said, "It's from the fermentation tank."

"Ew, no wonder it stinks."

"Jack just drank one. He made me drink one."

Ricky snorted. "What'd you do that for? Jeez, I'm surprised you didn't puke."

"I almost did. Jack wants all of you to drink one, too."

Bobby laughed. "Yeah? What for?"

"To make sure none of you is infected."

Ricky frowned. "Infected? What do you mean, infected?"

"Jack says that Charley was harboring the swarm inside his body, so maybe the rest of us are, too. Or some of us. So you drink this virus, and it'll kill the bacteria inside you, and kill the swarm."

Bobby said, "Are you serious? Drink that crap? No way, Mae!"

She turned to Vince.

"Smells like shit to me," Vince said. "Let someone else try it first."

Mae said, "Ricky? You want to be the first?"

Ricky shook his head. "I'm not drinking that. Why should I?"

"Well, for one thing, you'd be assured you weren't infected. And for another, we would be assured, too."

"What do you mean, it's a test?"

Mae shrugged. "That's what Jack thinks."

Julia frowned. She turned to Mae. "Where is Jack now?" she said. "I don't know. The last time I saw him was by the fermentation chambers. I don't know where he is now."

"Yes, you do," Julia said coldly. "You know exactly where he is."

"I don't. He didn't tell me."

"He did tell you. He tells you everything," Julia said. "In fact, you and he planned this little interlude, didn't you? You couldn't seriously expect us to drink that stuff. Where is Jack, Mae?"

"I told you, I don't know."

Julia said to Bobby, "Check the monitors. Find him." She came around the table. "Now then, Mae." Her voice was calm, but full of menace. "I want you to answer me. And I want you to tell me the truth."

Mae backed away from her. Ricky and Vince were closing in on either side of her. Mae backed against the wall.

Julia advanced slowly. "Tell me now, Mae," she said. "It will be much better for you if you cooperate."

From the other side of the room, Bobby said, "I found him. He's going through the fab room. He's carrying a jug of the crap, looks like."

"Tell me, Mae," Julia said, leaning close to Mae. She was so close their lips were almost touching. Mae squeezed her eyes and her lips tightly shut. Her body was beginning to shake with fear. Julia caressed her hair. "Don't be afraid. There's nothing to be afraid of. Just tell me what he is doing with that jug," Julia said.

Mae began to sob hysterically. "I knew it wouldn't work. I told him you would find out."

"Of course we would," Julia said quietly. "Of course we would find out. Just tell now."

"He took the jug of virus," Mae said, "and he's putting it in the water sprinklers."

"Is he?" Julia said. "That's really very clever of him. Thank you, sweetie." And she kissed Mae on the mouth. Mae squirmed, but her back was against the wall, and Julia held her head. When Julia finally stepped back, she said, "Try and stay calm. Just remember. It won't hurt you if you don't fight against it."

And she walked out of the room.

DAY 7

6:12 A.M.

Things happened faster than I expected. I could hear them running toward me down the corridor. I hastily hid the jug, then ran back and continued crossing the fabrication room. That was when they all came after me. I started to run. Vince tackled me, and I hit the concrete floor hard. Ricky threw himself on top of me after I was down. He knocked the wind out of me. Then Vince kicked me in the ribs a couple of times, and together they dragged me to my feet to face Julia.

"Hi, Jack," she said, smiling. "How's it going?"

"It's been better."

"We've had a nice talk with Mae," Julia said. "So there's no point in beating around the bush." She looked around the floor nearby. "Where is the jug?"

"What jug?"

"Jack." She shook her head sadly. "Why do you bother? Where is the jug of phage you were going to put in the sprinkler system?"

"I don't have any jug."

She stepped close to me. I could feel her breath on my face. "Jack ... I know that look on your face, Jack. You have a plan, don't you? Now tell me where the jug is."

"What jug?"

Her lips brushed mine. I just stood there, still as a statue. "Jack darling," she whispered, "you know better than to play with dangerous things. I want the jug." I stood there.

"Jack ... just one kiss ..." She was close, seductive.

Ricky said, "Forget it, Julia. He's not afraid of you. He drank the virus and he thinks it'll protect him."